Alberto Rebaudi

Implant success, survival, and failure: the International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference.

The primary function of a dental implant is to act as an abutment for a prosthetic device, similar to a natural tooth root and crown. Any success criteria, therefore, must include first and foremost support of a functional prosthesis. In addition, although clinical criteria for prosthetic success are beyond the scope of this article, patient satisfaction with the esthetic appearance of the implant restoration is necessary in clinical practice. The restoring dentist designs and fabricates a prosthesis similar to one supported by a tooth, and as such often evaluates and treats the dental implant similarly to a natural tooth. Yet, fundamental differences in the support system between these entities should be recognized. The purpose of this article is to use a few indices developed for natural teeth as an index that is specific for endosteal root-form implants. This article is also intended to update and upgrade what is purported to be implant success, implant survival, and implant failure. The Health Scale presented in this article was developed and accepted by the International Congress of Oral Implantologists Consensus Conference for Implant Success in Pisa, Italy, October 2007.

The effect of thread pattern upon implant osseointegration

OBJECTIVES Implant design features such as macro- and micro-design may influence overall implant success. Limited information is currently available. Therefore, it is the purpose of this paper to examine these factors such as thread pitch, thread geometry, helix angle, thread depth and width as well as implant crestal module may affect implant stability. SEARCH STRATEGY A literature search was conducted using MEDLINE to identify studies, from simulated laboratory models, animal, to human, related to this topic using the keywords of implant thread, implant macrodesign, thread pitch, thread geometry, helix angle, thread depth, thread width and implant crestal module. RESULTS The results showed how thread geometry affects the distribution of stress forces around the implant. A decreased thread pitch may positively influence implant stability. Excess helix angles in spite of a faster insertion may jeopardize the ability of implants to sustain axial load. Deeper threads seem to have an important effect on the stabilization in poorer bone quality situations. The addition of threads or microthreads up to the crestal module of an implant might provide a potential positive contribution on bone-to to-implant contact as well as on the preservation of marginal bone; nonetheless this remains to be determined. CONCLUSIONS Appraising the current literature on this subject and combining existing data to verify the presence of any association between the selected characteristics may be critical in the achievement of overall implant success.

Implant primary stability determined by resonance frequency analysis: correlation with insertion torque, histologic bone volume, and torsional stability at 6 weeks.

Objective:To determine if resonance frequency analysis (RFA) correlated with insertion torque (IT), bone volume (BV), and clinical osseointegration at 6 weeks. Materials and Methods:For 18 patients, BV was evaluated histologically by retrieving bone core biopsies before placement of 40 dental implants. Peak IT was recorded at implant placement, and RFA values (implant stability quotient [ISQ]) were noted at baseline, 3 weeks, and 6 weeks. Osseointegration was evaluated at 6 weeks when torquing abutments to 30 N. ISQ values were correlated with IT, BV and abutment torquing results. Data were statistically analyzed. Results:ISQ values significantly decreased at 3 weeks and increased at 6 weeks. There was a significant positive correlation between BV and ISQ at baseline and at 3 weeks, but not at 6 weeks, and between ISQ and jaw location, implant diameter and IT at baseline, 3 weeks, and 6 weeks. There was a significant correlation between spinning/painful implants during abutment torquing and low ISQ, low BV, and low IT values. Conclusion:Correlations between BV and IT values, and ISQ suggest that RFA may indicate primary implant stability. BV, IT, and ISQ values may anticipate the degree of osseointegration at 6 weeks.

Ultrasonic Implant Site Preparation Using Piezosurgery: A Multicenter Case Series Study Analyzing 3,579 Implants with a 1- to 3-Year Follow-Up

This multicenter case series introduces an innovative ultrasonic implant site preparation (UISP) technique as an alternative to the use of traditional rotary instruments. A total of 3,579 implants were inserted in 1,885 subjects, and the sites were prepared using a specific ultrasonic device with a 1- to 3-year follow-up. No surgical complications related to the UISP protocol were reported for any of the implant sites. Seventy-eight implants (59 maxillary, 19 mandibular) failed within 5 months of insertion, for an overall osseointegration percentage of 97.82% (97.14% maxilla, 98.75% mandible). Three maxillary implants failed after 3 years of loading, with an overall implant survival rate of 97.74% (96.99% maxilla, 98.75% mandible).

Peak insertion torque correlated to histologically and clinically evaluated bone density.

Objective:Establish a correlation between dental implant insertion torque (IT) and bone density. Materials and Methods:In 18 patients, implant site preparation was initiated using a trephine drill to retrieve a bone biopsy and completed with standard drills. Bone type was assessed during drilling according to surgeons tactile sense. Forty implants were placed and peak IT values were recorded. Osseointegration was evaluated clinically at abutment connection. Data were analyzed using Pearson product-moment correlation coefficient. Results:All implants but one achieved osseointegration. D1 and D4 bone types were significantly assessed using tactile sense. IT values ranged from 15 to 150 Ncm with a mean value of 78.30 Ncm. Mean IT was significantly higher in D1 bone (126.67 Ncm) and lower in D4 bone (40.22 Ncm) (P value <0.0001), whereas intermediate values were noted in D2 and D3 bone with no significant difference between these bone types (P value = 0.462). Statistically significant correlation was found between bone volume and IT values (r = +0.771, P < 0.0001). No statistically significant correlation was found between implant length and/or diameter and IT in all bone densities. Conclusion:Clinical assessment of bone density during drilling may be achieved in hard and soft bone but not in intermediate densities. Increasing peak IT values correlated with increasing bone volume. High IT does not seem to alter osseointegration process.

A new HA/TTCP material for bone augmentation: an in vivo histological pilot study in primates sinus grafting.

Objective:Synthetic calcium phosphate bone substitutes are widely used in sinus graft procedures due to their osteoconductive and biocompatible properties. Hydroxyapatite (HA), beta-tricalcium phosphate (&bgr;-TCP), and HA/&bgr;-TCP composite are the most applied materials. The aim of this study was to propose a new mineralogical formulation, HA/tetracalcium phosphate (TTCP), as biomaterial for bone regeneration in the maxillary sinus. Methods:Sinus grafts were performed by using granules of a HA/TTCP blend and a collagen membrane. Bone response at time points of 14 and 17 weeks was histologically evaluated. Results:After 14 weeks of healing, histomorphometric analysis showed the formation of new bone trabeculae among HA/TTCP granules. After 17 weeks, the bone trabeculae were thicker and HA/TTCP granules were still present. Histomorphometric analysis revealed a bone graft contact (BGC) of 64%. Conclusions:After 17 weeks from implantation, HA/TTCP synthetic bone graft performed very well as osteoconductive material: BGC was found very high, and bone volume and vital bone showed an ideal bone density for implant placement. HA/TTCP granules are accounted for to accelerate new bone formation and to reduce the time needed for the graft healing, thus achieving high quantity of the new bone formed.

Microstructure of Titanium-Cement-Lithium Disilicate Interface in CAD-CAM Dental Implant Crowns: A Three-Dimensional Profilometric Analysis

BACKGROUND Peri-implantitis is an infection of the implant surface caused by adhesion of bacteria that generate bone resorption and sometimes even consequent implant loss. Both screw-retained and cemented fixed implants are affected. PURPOSE The purpose of this study is to investigate the morphological defects at the cemented interface between titanium abutment and ceramic crown, comparing different adhesive cements used to fill the marginal gap. MATERIALS AND METHODS Twelve computer-aided design-computer-aided manufacturing dental crowns were cemented to titanium abutments using three different resin composite cements. Sealed margins were polished using grommets with descending diamond particle size. Three groups of four crowns each were made according to the cement used, namely RelyX Unicem (3 M ESPE), Panavia F 2.0 (Kuraray), and NX3 (Nexus Kerr). Samples were analyzed using optical inspection, three-dimensional profilometry, and image analysis, including analysis of variance. RESULTS Although RelyX showed significantly lower root mean square surface roughness (4.4 ± 1.5 μm) than that of NX3 (7.0 ± 2.9 μm), it showed no significant difference with Panavia (3.7 ± 1.5 μm). The marginal gap was significantly wider in Panavia (149 ± 108 μm) as compared with NX3 (71 ± 45 μm) and Relyx (64 ± 34 μm). For all groups, homogeneous heights of both metal-cement and ceramic-cement gaps were observed. Moreover, all samples showed homogeneity of the margins and absence of instrumental bias, thus validating both procedure and materials. CONCLUSIONS When using the chosen polishing method, RelyX Unicem showed both low roughness and marginal width, and thus the smoothest and more continuous abutment-crown interlayer, promising a low probability of occurrence of peri-implantitis.

Changes in Sinus Membrane Thickness After Lateral Sinus Floor Elevation: A Radiographic Study.

PURPOSE To radiographically monitor sinus membrane swelling after lateral sinus floor elevation surgery at short and long healing periods. MATERIALS AND METHODS For 26 patients seeking posterior maxillary implant-supported reconstruction, 32 lateral sinus floor elevations were performed using Piezosurgery. Sinus membranes were grafted using synthetic calcium phosphate bone substitutes, and graft volume was measured in cubic centimeters for each case. Cone beam computed tomography (CBCT) examination was conducted preoperatively in all patients and for each grafted sinus at 1 day (n = 8), 2 days (n = 9), 3 days (n = 8), or 7 days (n = 7) after surgery. Control CBCT was then performed for all patients at 3, 6, and 12 months after surgery. Sinus membrane thickness was measured on cross-sectional CBCT images at nine standardized points per sinus, before lateral sinus floor elevation and at all postoperative examinations. RESULTS Mean sinus membrane thickness was 0.73 mm before surgery, and 5 mm, 4.1 mm, 5.9 mm, and 7 mm, respectively, at 1, 2, 3, and 7 days after surgery. First week combined postoperative CBCT measurements of membrane thickness was 5.4 mm, then 1.3, 0.68, and 0.39 mm at 3, 6, and 12 months, respectively, after surgery. Membrane thickness significantly increased the first week after surgery and gradually decreased significantly at 3, 6, and 12 months in all groups (P < .001). First-week postoperative measurements showed a significant increase in membrane thickness at 3 days compared with the 1- and 2-day results (P < .001) and at 7 days compared with all other time points (P < .001). Membrane thickness at 2 days did not change significantly compared with 1-day measurements. Larger graft volume was positively correlated with an increase in membrane thickness after surgery at all time points (n = 32; r = 0.527; P < .001). CONCLUSION After lateral sinus floor elevation surgery, transient swelling of sinus membrane is observed. It reaches a peak value 7 days after surgery and completely resolves over months. This swelling is correlated to the extent of sinus floor elevation.

Electrochemical coating of dental implants with anodic porous titania for enhanced osteointegration

Summary Clinical long-term osteointegration of titanium-based biomedical devices is the main goal for both dental and orthopedical implants. Both the surface morphology and the possible functionalization of the implant surface are important points. In the last decade, following the success of nanostructured anodic porous alumina, anodic porous titania has also attracted the interest of academic researchers. This material, investigated mainly for its photocatalytic properties and for applications in solar cells, is usually obtained from the anodization of ultrapure titanium. We anodized dental implants made of commercial grade titanium under different experimental conditions and characterized the resulting surface morphology with scanning electron microscopy equipped with an energy dispersive spectrometer. The appearance of nanopores on these implants confirm that anodic porous titania can be obtained not only on ultrapure and flat titanium but also as a conformal coating on curved surfaces of real objects made of industrial titanium alloys. Raman spectroscopy showed that the titania phase obtained is anatase. Furthermore, it was demonstrated that by carrying out the anodization in the presence of electrolyte additives such as magnesium, these can be incorporated into the porous coating. The proposed method for the surface nanostructuring of biomedical implants should allow for integration of conventional microscale treatments such as sandblasting with additive nanoscale patterning. Additional advantages are provided by this material when considering the possible loading of bioactive drugs in the porous cavities.

Standard Drilling Versus Ultrasonic Implant Site Preparation: A Clinical Study at 4 Weeks After Insertion of Conical Implants

Objective: Clinically evaluate implants placed after ultrasonic implant site preparation (UISP) and standard drilling (SD). Materials and Methods: Ten patients received 21 implants placed using UISP (n = 11) or SD (n = 10). Bone quality was hand assessed and final insertion torque (IT), resonance frequency analysis (ISQ) at baseline and ISQ, and removal torque values (RTV) at 4 weeks were recorded and compared. Results: Mean IT values were 70.91 and 72.40 N/cm in UISP and SD groups, respectively, and were not statistically different. IT significantly correlated to bone quality. Mean ISQ values at baseline and 4 weeks were not significantly different and were 74.72 and 74.73 for UISP and 76.70 and 73.20 for SD, respectively. Mean ISQ at baseline significantly correlated to IT values and bone quality in both groups. Mean RTV values in both UISP (51.32 N/cm) and SD (53.1 N/cm) were not significantly different but significantly correlated to IT values. All implants achieved osseointegration and were restored. Conclusion: Implant placement after ultrasonic preparation can be considered a predictable technique leading to clinical and biological responses similar to SD 4 weeks after insertion.